Experiment 12 – File Handling – Student Records

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

// Structure definition
struct Student {
    int rollNumber;
    char name[50];
    float marks[3];
    float total;
    float percentage;
};

// Function to write student record to file
void writeToFile(struct Student s) {
    FILE *fp;
    fp = fopen("students.txt", "a");  // "a" for append mode
    
    if (fp == NULL) {
        printf("Error opening file for writing!\n");
        return;
    }
    
    // Write student data to file
    fprintf(fp, "%d %s %.2f %.2f %.2f %.2f %.2f\n",
            s.rollNumber, s.name, s.marks[0], s.marks[1], 
            s.marks[2], s.total, s.percentage);
    
    fclose(fp);
    printf("Student record saved to file successfully!\n");
}

// Function to read all student records from file
void readFromFile() {
    FILE *fp;
    struct Student s;
    
    fp = fopen("students.txt", "r");  // "r" for read mode
    
    if (fp == NULL) {
        printf("Error opening file for reading!\n");
        printf("File may not exist. Please add some records first.\n");
        return;
    }
    
    printf("\n========== STUDENT RECORDS FROM FILE ==========\n");
    printf("%-10s %-20s %-8s %-8s %-8s %-8s %-10s\n",
           "Roll No", "Name", "Mark1", "Mark2", "Mark3", "Total", "Percentage");
    printf("-----------------------------------------------------------\n");
    
    // Read until end of file
    while (fscanf(fp, "%d %s %f %f %f %f %f",
                  &s.rollNumber, s.name, &s.marks[0], &s.marks[1],
                  &s.marks[2], &s.total, &s.percentage) != EOF) {
        
        printf("%-10d %-20s %-8.2f %-8.2f %-8.2f %-8.2f %-10.2f\n",
               s.rollNumber, s.name, s.marks[0], s.marks[1],
               s.marks[2], s.total, s.percentage);
    }
    
    fclose(fp);
}

int main() {
    struct Student s;
    int choice, n, i;
    
    do {
        printf("\n========== FILE HANDLING MENU ==========\n");
        printf("1. Add Student Record to File\n");
        printf("2. Display All Records from File\n");
        printf("3. Exit\n");
        printf("Enter your choice: ");
        scanf("%d", &choice);
        
        switch(choice) {
            case 1:
                printf("\nEnter number of students to add: ");
                scanf("%d", &n);
                
                for (i = 0; i < n; i++) {
                    printf("\n--- Student %d ---\n", i + 1);
                    printf("Roll Number: ");
                    scanf("%d", &s.rollNumber);
                    
                    printf("Name: ");
                    scanf(" %[^\n]", s.name);
                    
                    printf("Enter marks for 3 subjects:\n");
                    printf("Subject 1: ");
                    scanf("%f", &s.marks[0]);
                    printf("Subject 2: ");
                    scanf("%f", &s.marks[1]);
                    printf("Subject 3: ");
                    scanf("%f", &s.marks[2]);
                    
                    s.total = s.marks[0] + s.marks[1] + s.marks[2];
                    s.percentage = (s.total / 300) * 100;
                    
                    writeToFile(s);
                }
                break;
                
            case 2:
                readFromFile();
                break;
                
            case 3:
                printf("Exiting program.\n");
                break;
                
            default:
                printf("Invalid choice!\n");
        }
    } while (choice != 3);
    
    return 0;
}